球型聚丙烯颗粒振动带电特性影响实验研究

Experimental Study on the Effect of Vibration Charging Characteristics of Spherical Polypropylene Particles

为研究化工物料颗粒在振动过程中带电特性影响因素及影响规律,采用球形聚丙烯(PP)单/多颗粒在筛分仪内振动带电方式,分别在不同筛分仪振荡幅度、振荡时间、环境湿度以及不同PP颗粒粒径、振动颗粒总数目的条件下,对PP颗粒带电速率及带电饱和量进行测试。结果表明:振荡幅度、振荡时间、环境湿度及颗粒粒径等因素对PP单颗粒静电带电速率及带电饱和量均有重要影响;环境湿度越大,颗粒带电量越小;随筛分仪振幅增加,颗粒振荡摩擦越剧烈,促进了颗粒-筛网壁间电荷转移,颗粒带电量增大;随振荡时间的增加,颗粒带电呈指数型增加并趋于饱和,同时其饱和带电量随颗粒粒径的增大而增大。但颗粒粒径增大,颗粒质量增加,导致颗粒带电荷/质比减小。通过控制粒径及振荡和筛分时间,可合理控制绝缘聚烯烃颗粒产品静电带电量。

To study the charging characteristics of the polymer particles,the charging speed and the saturation charge of single/multiple spherical PP particles were investigated in a shaking apparatus with different shaking amplitudes,shaking time,environment humidities and particle sizes.The results show that the shaking amplitude,shaking time,environmental humidity,and particle size have an important effect on the charging speed and saturation charge of single PP particles.The higher the environmental humidity,the lower the particle charge.The bigger the shaking amplitude,the stronger the collision and friction of the particles against the metal wall,which increases the charge transfer between the particles and the wall,and the charges of particles.As the oscillation time increases,the charge of the particle grows exponentially until saturation,and the saturation charge is determined by the particle size,of which the bigger the particle,the higher the particle saturation charge.However,the bigger particle leads to more mass,which makes the charge/mass ratio smaller.In short,the triboelectic charge of the polyolefin particle can be reasonably manipulated by controlling the particle size and charging time.